Fuel for compression ignition engines



Patented June 3, 1941 FUEL FOR COMPRESSION IGNITION EN GIN Ernest M.Marks, Lansdowne, Pa., assignor to The Atlantic Refining Company,

Philadelphia, Pa.,

a corporation of Pennsylvania No Drawing. Application June 1, 1938,Serial No. 211,208

2 Claims.

The present invention relates to improvements in compressionignition'fuels, and relates more.

particularly to the use of nitrosites and/or nitrosates as ignitionaccelerators for hydrocarbon fuels of the compression ignition type.

A principal object of this invention is the improvement of Diesel enginefuels, and particularly of fuels adapted for use in high-speedcompression ignition engines, whereby there is obtained a reduction inthe ignition temperature of the fuel oil and a reduction of the delayperiod between the injection and ignition of the fuel oil.

In accordance with this invention improved compression ignition fuelsmay be obtained by reacting olefine hydrocarbons or hydrocarbon mixturescontaining olefines with an oxide of nitrogen, particularly nitrogentrioxide or nitrogen tetroxide, to form nitrosites or nitrosates,respectively, and thereafter adding the nitrosite or nitrosate to fueloil in an amount suflicient to substantially increase the cetane numberof the fuel oil. Or, fuel oil containing olefines may be treateddirectly with the aforesaid oxides of nitrogen, thereby producing fromthe unsaturated oil components, nitrosites or nitrosates which remain insolution in the fuel oil. Such treated fuel oil may be employed directlyas a compression ignition fuel, or may be diluted to the desired extentwith untreated fuel oil. In either case a fuel of improved cetane numberis obtained, the increased cetane number being reflected in a loweringof the ignition temperature of the fuel oil and in a reduction in thedelay period between injection and ignition of the fuel.

Among the hydrocarbons or hydrocarbon mixtures which may be employed inthe preparation of nitrosites and/or nitrosates are included olefines,preferably such aspropylene, butylene, isobutylene, di i'sobutylene, triisobutylene, amylene, di amylene, methyl pentene, methyl hexene, ethylhexene, dimethyl octene, decene, dodecene, pinene, and the like. Varioushydrocarbon mixtures containing olefines which may be utilized arekerosine, gas oils, and particularly cracked J1 recycle gas oils boilingsubstantially within the range of from about 400 F. to about 750 F.Unsaturated kerosine, gas oil or'higher boiling )i1 fractionsproducedbysolvent extraction with ;elective solvents suchas liquefied sulfurdioxide, ahenol, furfural, chlorex, aniline, ,nitrobenzene Jr cresylicacid m y likewise be suitably em- )loyed. 1

The following examples are illustrative of the 'esults which-may beobtained in the practice of he present invention. The cetane number ofhe fuel is employed herein as an index of the ualityof the fuel, and animprovement in the uel is expressed by an increase in the cetane lumber.a I

(1) 3540 parts by weight of a gas oil resulting over anhydrous (N203)generated by weight of AS203.

period being about 2 hours.

from the production of gasoline by cracking a high boiling petroleum oiland having a boiling range of 281 F. to 605 R, an Al P. I. gravity of28.3, and an aniline number of 86 was treated with nitrogen. tetroxide(N02) generated by the action of 500 parts by weight of concentratedHN03 upon 150 parts by weight of NaN02. The treatment was carried on ata temperature of about 50 F., the reaction period being about 2 hours.The treated gas oil containing nitrosates resulting from the reaction ofthe N02 upon unsaturated components of the oil, was thoroughly washedwith water to remove unreacted N02. The washed oil was then dried overanhydrous CaCl2 and tested for increase in cetane number. The cetanenumber of the untreated gas oil was found to be 28, whereas the cetanenumber of the treated gas oil containing nitrosates was found to be 42.

(2) 3200 parts by boiling range of 220 gravity of 34.8" was treated withnitrogen tetroxide (N02) generated by the action of 500 parts by weightof concentrated HNOs upon 150 parts by weight of NaN02. The treatmentwas carried on at a temperature of about 50 F., the reaction periodbeing about 2 hours. The treated gas oil containing nitrosates resultingfrom the reaction of the N02 upon unsaturated components of the oil, wasthoroughly washed with water to remove unreacted N02. The washed oil wasthendried CaCl2 and tested for increase in cetane number. The cetanenumber of the untreated gas oil' was found to be 37, whereas the cetanenumber of the treated gas oil containing nitrosates was found to be 56.

(3) 450 parts by weight of the gas oil used in Example 1 was treatedwith nitrogen trioxide the action of 500 parts by weight of concentratedHNO; upon parts by The treatment was carried out of about 80 F., thereaction The treated .gas oil containing nitrosites resulting from. thereaction of the N203 upon unsaturatedycomponents of the oil wasthoroughly washed with water to removeunreacted N202 and then dried overanhydrous CaCla, 5 parts by volume of the treated oil was admixed withparts by volume of gas oil having a. boiling range of 390 F. to 672 R,an A. P. I. gravity M302", and an aniline number of 157. The cetanenumber of the unblended gas oil was found to be 49, whereas the cetancnumber of the blended fuel containing 5% of treated oil was found to be55.

(4) 225 parts by weight of the gas oil used in Example 1 was dilutedwith 450 parts by weight of diethyl ether and treated with nitrogentetroxide (N02) generated by the action 'oflhOO weight of gas oil havinga F. to 614 R, an A. P. I.

at a. temperature and an aniline number of 124 parts by weight ofconcentrated HNO; upon 170 parts by weight of NaNO2. The treatment wascarried out at a temperature of about 32 F., the reaction period beingabout 1 hours. The ether solution of the treated gas oil containingnitrosites resulting from the reaction of the N02 upon unsaturatedcomponents of the oil was thoroughly washed with water to removeunreacted N02, the solution then dried, and the ether removed byvaporization. 5 parts by volume of the treated oil was admixed with 95parts by volume of gas oil having a boiling range of 390 F. to 672 R, anA. P. I. gravity of 302, and an aniline number of 157. The cetane numberof the unblended gas oil was found to be 49, whereas the cetane numberof the blended fuel containing 5% of treated oil was found to be 53.

(5) 225 parts by weight of gas oil having a boiling range of 220' F. to614 R, an A. P. I. gravity of 34.8", and an aniline number of 124 wasdiluted with 450 parts by weight of diethyl ether and treated withnitrogen trioxide (N203) generated by the action of 500 parts by weightof concentrated HNOs upon 75 parts by weight of AS203. The treatment wascarried out at a temperature of about 32 F., the reaction period beingabout 2 hours. The ether solution of the treated gas oil containingnitrosites resulting from the reaction of the N203 upon unsaturatedcomponents of the oil was thoroughly washed with water to removeunreacted N203, the solution then dried, and the ether removed byvaporization. 5 parts by volume of the treated oil was admixed with 95parts by volume of gas oil having a boiling range of 390 F. to 672 F.,an A. P. I. gravity of 30.2", and an aniline number of 157. The cetanenumber of the unblended gas oil was found to be 49. whereas the cetanenumber of the blended fuel containing 5% of treated oil was found to be55.

(6) 225 parts by weight of gas oil used in Example 5 was diluted with450 parts by weight of diethyl ether and treated with nitrogen tetroxide(N02) generated by the action of 500 parts by weight of concentratedHNOs upon 170 parts by weight of NaNO::. The treatment was carried outat a temperature of about 32 F., the reaction period being about 1 /2hours. The ether solution of the treated gas oil containing nitrositesresulting from the reaction of the N02 upon unsaturated components ofthe oil was throughly washed with water to remove unreacted N02, thesolution then dried, and the ether removed by vaporization. 5 parts byvolume of the treated oil was admixed with 95 parts by volume of gas oilhaving a boiling range of 390 F. to 672 R, an A. P. I. gravity of 30.2",and an aniline number of 157. The cetane number of the unblended gas oilwas found to be 49, whereas the cetane number of the blended fuelcontaining 5% of treated oil was found to be 53.

(7) 100 parts by weight of commercial diamylene having a boiling rangeof 302 F. to 338 F., and an A. P. I. gravity of 51.5 was diluted with300 parts by weight of diethyl ether and treated with nitrogen trioxide(N203) generated by the action of 450 parts by weight of concentratedHNO3 upon 50 parts by weight of AS203. The treatment was carried out ata temperature of about 50 F.. the reaction period being about 2 hours.The ether solution of diamylene nitrosite resulting from the reaction ofthe N202 upon the diamylene was thoroughly washed with water to removeunreacted N203, the solution then dried, and the ether removed byvaporization. 3 parts by volume of the diamylene nitrosite was admixedwith 97 parts by volume of a Diesel reference fuel consisting of 60% byvolume of straight-run, parafiinic gas oil and 40% by volume of a-methylnaphthalene. The cetane number of the reference fuel was found to be 44,whereas the cetane number of the blended fuel containing 3% of diamylenenitrosite was found to be 54.

(8) 100 parts by weight of commercial diamylene used in Example 7 wasdiluted with 300 parts by weight of diethyl ether and treated withnitrogen tetroxide (N02) generated by the action of 400 parts by Weightof concentrated HNO3 upon parts by weight of NaNO2. The treatment wascarried out at a temperature of about 50 F., the reaction period beingabout 2 hours. The ether solution of diamylene nitrosate resulting fromthe reaction of the N02 upon the diamylene was thoroughly washed withwater to remove unreacted N02, the solution then dried, and the etherremoved by vaporization. 3 parts by volume of the diamylene nitrosatewas admixed with 97 parts by volume of 9. Diesel reference fuelconsisting of 60% by volume of straight-run, parafiinic gas oil and 40%by volume of a-methyl naphthalene. The cetane number of the referencefuel was found to be 44, whereas the cetane number of the blended fuelcontaining 3% of diamylene nitrosate was found to be 55.

It will be seen, from the above examples, that a marked improvement inthe cetane number of compression ignition fuels is obtained by theaddition thereto or the formation therein of, nitrosites and/ornitrosates of unsaturated hydrocarbons.

Among the advantages which accrue from the use of nitrositesand/or-nitrosates as ignition accelerators in compression ignition fuelsmay be mentioned:

(1) Elimination of knocking and rough-running by decreasing the ignitionlag.

(2) Easier starting due to the reduced spontaneous ignition temperaturesof the blended fuel.

(3) Possibility of using inferior grade of fuel oil. By the addition ofthe accelerator, low grade fuels which at present are unsuitable for usein compression ignition engines, may be rendered equal or superior tohigh grade unblended fuels.

The above description and examples are to be taken as illustrative onlyand not as limiting the scope of'the invention. Any modification orvariation therefrom which conforms to the spirit of the invention isintended to be included within the scope of the claims.

In the appended claims the term gasoline boiling range refers to atemperature range of the order of about 90 F. to 390 F.

. What I claim is:

1. A compression ignition fuel comprising fuel oil boiling above thegasoline boiling range and a compound from the group consisting ofdiamylene nitrosite and diamylene nitrosate, said compound being presentin an amount sufficient to substantially increase the cetane number ofthe fuel oil.

2. A compression ignition fuel comprising fuel oil boiling from about400 F. to about 750 F. and a compound from the group consisting ofdiamylene nitrosite and diamylene nitrosate, said compound being presentin an amount suflicient to substantially increase the cetane number ofthe fuel oil.

ERNEST M. MARKS.

